JPS59203883A - Operation of variable speed pump water wheel dynamotor - Google Patents

Abstract

PURPOSE:To rotate the pump water wheel in a stable predetermined speed by effecting the opening degree control of a guide valve preferentially only when a pump input is decreasing. CONSTITUTION:A speed control command is delayd than the opening degree control command of a guide valve 10 by the switching of a switching means 4b only when the pump input is decreasing. According to this method, the speed control response speed of the dynamotor 1 is delayed, therefore, the response speed approaches in some degree to the guide valve opening degree control having a mechanical system. Accordingly, the rotating speed of the water wheel will never pass an unstable zone when the pump input is decreasing, the water wheel 2 rotates in a stable predetermined speed at all times and the operation of the dynamotor may be effected without generating vibration or noise.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method of operating a variable speed pump water turbine generator/motor, and in particular to a winding induction power generation system in which variable speed operation is performed by alternating current excitation of the secondary winding. This relates to a method of operating an electric motor.

[Background of the invention]

The pump operation of this type of variable-speed pump-turbine generator-motor, which has been generally adopted in the past, is to apply alternating current at a predetermined frequency to the secondary winding according to the required rotational speed of the motor, and synchronize it with the input frequency on the negative side. That's what I do. That is, this species,
The electric motor system is constructed as shown in FIG. 1 and operated as follows. That is, in this type of system, a wound induction generator motor 1 is used as an electric motor, this wound induction motor 1 drives a pump water turbine 2 directly connected to its rotor, and a secondary winding 1a is driven by a cycloconverter 3. , is excited and variable speed operation is performed. 4 is a speed control device which determines the optimum excitation current and speed from the outputs of the system phase detector 6, speed detector 7, phase detector 8 and water level detector 9 according to the Yoei active power from the system 5; Controls the cyclocomputer 3 and guide valve 10. In this system, the speed of the induction motor 1 is controlled by a speed control device 4 controlling a scissor converter 3 to change the amount of excitation.

If there is a request from the system to reduce the pump input during pump operation, the electric motor will respond by slowing down and the guide valve will reduce its opening. Figure 2 shows the relationship between the speed of the pump-turbine and the amount of water at this point. This figure is a complete characteristic diagram of the pump-turbine, with point A at maximum output operation and point B at minimum output operation.

This transition from point A to point B is performed by speed control and guide valve opening control. If speed control and guide valve opening control are performed independently, speed control is only an electrical system, but guide valve opening control involves mechanical systems such as hydraulic equipment.
The response speed is faster with speed control, and the transition route from point A to point B is the route indicated by the dotted line in the figure. This route indicated by the dotted line passes through an area where the operating point of the pump-turbine is unstable, which is unfavorable for the operation of the Sibompu-turbine.

In other words, to explain this unstable region in detail using Figure 3, this figure shows a part of Figure 2, where the vertical axis is the flow rate Q1 per unit head, and the horizontal axis is the unit head. Number of revolutions per unit 111, that is, nl = n/)i where n: number of revolutions, H: head.

As is clear from this relationship, even if the rotational speed n is constant, the head H
When changes, the number of revolutions per unit head n.

Also fluctuates. Therefore, the guide valve opening is now 40 degrees.

At point X where 11+=1.75, if a variation of ±Δn occurs in the number of rotations per unit head, then the flow rate variation in this case is ΔQI! It is. However, the guide valve opening is 100%.
At point Y where n=1.76, the number of revolutions per unit head ±Δn,
The flow rate fluctuation is ΔQ+y, which is several times larger than the former flow rate fluctuation ΔQ+x.

Since this large fluctuation in flow rate causes noise and vibration, it is preferable that the guide valve opening degree be as small as possible even when lowering the number of rotations per unit head.

In this regard, as mentioned above, in the conventional type, the rotational speed is lowered when the guide valve opening is large, which tends to cause vibrations and noise in the waterwheel.

[Purpose of the invention]

The present invention has been made with this in mind, and therefore, its object is a method of operating a pump-turbine generator-motor in which the pump-turbine always rotates stably at a predetermined speed and does not generate vibration or noise. is to provide.

[Summary of the invention]

That is, the present invention achieves the intended purpose by controlling the opening degree of the guide valve that adjusts the amount of water with priority over the speed control of the speed control device of the induction generator motor only when the pump input is reduced. This is how it was done.

[Embodiments of the invention]

The present invention will be described in detail below based on the illustrated embodiments.

Fig. 4 shows a power generation system for explaining the operating method of the present invention, and the same parts as in Fig. 1 are given the same reference numerals. Explanation will be omitted. The speed control device 4 plays the role of determining the optimum excitation current and speed of the motor from the output signals of the system phase detector 6, speed detector 7, phase detector 8, and water level detector 9, as in the conventional case, and controls the generator motor. Speed control and guide valve opening control are carried out, and in this case, the speed control device 4 of the present invention is particularly constructed and operated as follows.

That is, it is shown as 4a in the figure. L sea urchin? 1Vt
A temporary suppression device is provided in the speed command circuit of machine h, and a switching means 4b is provided therefor, so that only when the pump input decreases, the opening control command of the guide valve and the speed control command are delayed by switching the switching means 4b. It is to make it. In other words, guide valve opening control is given priority over motor speed control only when the pump input is reduced.

That is, to explain the operation using the complete characteristic diagram of the pump-turbine shown in Fig. 5, when transitioning from point A of maximum output operation to point B of minimum output operation, the guide valve is opened for a certain period of time as shown by point 1vjIFL+. Prioritizes control and operates
After the certain period of time has elapsed, the speed control is started.

If this is done, the speed control response speed of the generator motor will be slow, so the response speed will approach the guide valve opening control with a mechanical system to some extent, and the pump will not go through the unstable region as in the past when the human power is reduced. The waterwheel always rotates stably at a predetermined speed and no longer generates vibration or noise.

In this case, the reason why the guide valve opening degree control is given priority over the speed control and is controlled only when the pump input is reduced is as follows. In other words, if guide valve opening control is always given priority over speed control, when the pump input increases, for example, when moving from point B of minimum output operation to point A of maximum output operation, the fifth
There is a possibility that the path will be as shown by the two-dot chain line R2 in the figure, approaching the unstable region of the pump-turbine. Therefore, in this case, it is necessary to cancel the priority of guide valve opening degree control over speed control. For the above reasons, it is important to give priority to the guide valve opening control over the speed control only when the pump input decreases.

The above explanation has been about the case where a temporary suppression device is provided in the speed command circuit of the electric motor as an example, but it does not always have to be done this way. It may be possible to manually delay the speed control, or it may be possible to set the speed control response speed slow to 1 in advance.

The transition state in this case is indicated by the dotted line R3 in FIG.

〔Effect of the invention〕

As explained above, according to the operating method of the present invention, the opening control of the guide valve is given priority over the speed control of the electric motor when the pump input decreases, so the operating state of the pump-turbine becomes unstable. A method for operating a variable speed pump-turbine generator-motor which always rotates stably at a fixed speed without entering the range and does not generate vibration or noise can be obtained.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional generator-electric system, Figure 2 is a complete characteristics diagram of a pump-turbine showing the transition state when the pump input is reduced by the conventional operation method, and Figure 3 is a diagram of the pump turbine shown in Figure 2. A partially enlarged view, FIG. 4 is a block diagram showing the generator-motor system for explaining the operating method of the present invention, and FIG. 5 is a complete diagram of the pump-turbine showing the transition state when the pump input is reduced according to the operating method of the present invention. It is a characteristic diagram. 1... Wound induction generator motor, 2... Pump water turbine,
3...Cycloconverter, 4...Speed control device,
6... System phase detector, 7... Speed detector, 8...
- Phase detector, 9... Water level detector, 10... Guide valve. Agent Patent Attorney Akio Takahashi / Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A wound-type induction generator-motor, a speed control device for controlling the speed of the wound-type induction generator-motor, a pump-turbine that drives the wound-type induction generator-motor during power generation and is driven during pumping; and a guide valve that adjusts the amount of water supplied, applies alternating current excitation to the secondary winding of the wound induction generator, and controls the speed control device and the opening angle of the guide valve to perform variable speed operation. In the method for operating a variable speed pump water turbine generator motor, the opening angle control of the guide valve is prioritized over the speed change control of the speed control device when reducing the output of the pump during pump operation. A method of operating a variable speed pump water turbine generator motor, characterized in that the variable speed pump water turbine generator motor is operated.